The present invention relates to binocular optical devices, and more specifically, to a binocular having improved functioning ability in a wet or harsh environment.
A binocular intended for use in a wet or harsh environment, a so-called waterproof binocular, poses special design constraints. For example, the binocular may be designed to have all the functions of a conventional binocular, yet every screw, seal, and interface must be impervious to the penetration of water. Moreover, all the components of a harsh environment binocular must be more rugged in construction than those of a conventional binocular. Balancing the constraints of construction for harsh environments while maintaining facility of use poses a particular problem.
For example, a conventional binocular may have thin rubber eye cups to fit the eye of a user. If the user wears spectacles, the eye cups are conventionally designed to fold back over the eyepieces of the conventional binocular, allowing the lenses of a pair of spectacles to become closer to the eyepieces. In a harsh environment, the thin rubber eye cup is inappropriate as it may be subject to wear, degradation from sunlight, tearing, or other hazards. Furthermore, the use of a thin rubber eye cup may not be practical when the eyepieces themselves are rubberized or armored, therefore having a larger diameter. Yet, the binocular must still allow the user with spectacles to use the binocular without removing his spectacles.
Furthermore, a conventional binocular is also provided with a strap and strap-holding loops provided to the binocular body. The strap is typically loosely strung through the loops. However, the strap-holding loops may be fixed to the binocular with screws or other means which could allow the entry of water or dirt, in a harsh environment. The relative position of the loose strap and the binocular itself easily changes, which can be troublesome. The strap holding loops and loose strap do not provide for the adjustability necessary for a harsh environment tool.
Yet further, any binocular must have adjusting mechanisms both for focusing and for diopter correction. The diopter correction mechanism is used to correct for differences between a user's left and right eyes, and conventionally moves only one of a pair of optical elements that are used by the focusing mechanism. In a pair of harsh environment binoculars, both mechanism must be waterproof, yet easily accessible to the user. At the same time, the number of waterproof (sealed) interfaces should be minimized.